颤振镖json未处理异常：InternalLinkedHashMap<；字符串，动态>'；不是类型为'；列表<；动态>；

我从另一个问题中得到了这个代码（感谢chunhunghan）。我需要做一个登录屏幕，我试图根据服务器返回给我的响应验证用户凭据，但每次我尝试运行代码时，它都会给我“未处理的异常：InternalLinkedHashMap”不是“List”类型错误的子类型，我不确定如何修复它

这就是模型：

import 'dart:convert';
Payload payloadFromJson(String str) => Payload.fromJson(json.decode(str));

String payloadToJson(Payload data) => json.encode(data.toJson());

class Payload {
  Payload({
    this.version,
    this.encoding,
    this.subsonicResponse,
  });

  String version;
  String encoding;
  SubsonicResponse subsonicResponse;

  factory Payload.fromJson(Map<String, dynamic> json) => Payload(
        version: json["version"],
        encoding: json["encoding"],
        subsonicResponse: SubsonicResponse.fromJson(json["subsonic-response"]),
      );

  Map<String, dynamic> toJson() => {
        "version": version,
        "encoding": encoding,
        "subsonic-response": subsonicResponse.toJson(),
      };
}

class SubsonicResponse {
  SubsonicResponse({
    this.status,
    this.version,
    this.xmlns,
    this.albumList,
  });

  String status;
  String version;
  String xmlns;
  AlbumList albumList;

  factory SubsonicResponse.fromJson(Map<String, dynamic> json) =>
      SubsonicResponse(
        status: json["status"],
        version: json["version"],
        albumList: AlbumList.fromJson(json["albumList"]),
      );

  Map<String, dynamic> toJson() => {
        "status": status,
        "version": version,
        "albumList": albumList.toJson(),
      };
}

class AlbumList {
  AlbumList({
    this.album,
  });

  List<AlbumsList> album;

  factory AlbumList.fromJson(Map<String, dynamic> json) => AlbumList(
        album: json["album"] == null ? null: List<AlbumsList>.from(json["album"].map((x) => AlbumsList.fromJson(x))),);

  Map<String, dynamic> toJson() => {
        "album": album == null ? null: List<dynamic>.from(album.map((x) => x.toJson())),
      };
}

class AlbumsList {
  AlbumsList({
    this.id,
    this.parent,
    this.isDir,
    this.title,
    this.album,
    this.artist,
    this.genre,
    this.coverArt,
    this.playCount,
    this.created,
    this.year,
  });

  String id;
  String parent;
  String isDir;
  String title;
  String album;
  String artist;
  String genre;
  String coverArt;
  String playCount;
  DateTime created;
  String year;

  factory AlbumsList.fromJson(Map<String, dynamic> json) => AlbumsList(
        id: json["id"],
        parent: json["parent"],
        isDir: json["isDir"],
        title: json["title"],
        album: json["album"],
        artist: json["artist"],
        genre: json["genre"],
        coverArt: json["coverArt"],
        playCount: json["playCount"],
        created: DateTime.parse(json["created"]),
        year: json["year"] == null ? null : json["year"],
      );

  Map<String, dynamic> toJson() => {
        "id": id,
        "parent": parent,
        "isDir": isDir,
        "title": title,
        "album": album,
        "artist": artist,
        "genre": genre,
        "coverArt": coverArt,
        "playCount": playCount,
        "created": created.toIso8601String(),
        "year": year == null ? null : year,
      };
}

---

这是api响应

将

payloadFromJson

更改为

Payload payloadFromJson (Map<String, dynamic>str) => Payload.fromJson(str);

Payload payloadFromJson（Mapstr）=>Payload.fromJson（str）；

如果json包含键，则从json获取值

 factory SubsonicResponse.fromJson(Map<String, dynamic> json) =>
      SubsonicResponse(
        status: json["status"],
        version: json["version"],
        albumList: json.containsKey("albumList")? AlbumList.fromJson(json["albumList"]):null,
      );

factory.fromJson（映射json）=>
亚音速响应(
状态：json[“状态”]，
版本：json[“版本”]，
albumList:json.containsKey（“albumList”）？albumList.fromJson（json[“albumList”]）：null，
);

将payloadFromJson更改为

有效载荷payloadFromJson（Mapstr）=>Payload.fromJson（str）

@Nidheesh刚刚尝试了这个方法，解决了这个错误，但由于某种原因，当我尝试打印对象时，它会显示null。你能发布json@Nidheesh是的，我用json数据更新了帖子。我如何将亚音速响应的状态与字符串进行比较？您可以在

string

Payload payloadFromJson (Map<String, dynamic>str) => Payload.fromJson(str);

 factory SubsonicResponse.fromJson(Map<String, dynamic> json) =>
      SubsonicResponse(
        status: json["status"],
        version: json["version"],
        albumList: json.containsKey("albumList")? AlbumList.fromJson(json["albumList"]):null,
      );